Pumps are rated in gallons per minute gpm and pump motors are rated in horsepower hp. Special water needs — such as for irrigation, heat pumps, or livestock — can increase peak demand and require a larger pump. The pump is placed directly into a 4" or larger well, below the water level. Jet pumps are most often used on wells that are 4 inches or less in diameter, such as drive-point or other shallow wells.
The pump may be located on top of the well — or it may be offset from the well in a pump house, and connected to the well with piping. Jet pumps typically have a lower operating pressure and a lower water yield than submersible pumps. Jet pumps operate by forcing water through a jet or venturi— a narrow, cone-shaped device which creates a partial vacuum suction and draws water from the well into the pumping system.
Shallow well jet pumps — which are used where the water is less than 25 feet below the surface — have the jet located in the pump itself. For deeper wells, the jet is located inside the well below the water level.
Pressure Tanks As the name implies, a pressure tank contains water under pressure. As water is pumped into the tank, it compresses the air in the tank until the pressure reaches a preset level — typically from 40 to 60 pounds per square inch psi — which automatically shuts off the pump.
When a faucet is opened, the air pressure in the tank forces water through the pipes until the pressure drops to another preset level — usually from 20 to 40 psi — which starts the pump again. A pressure switch starts and stops the pump at the preset pressure levels, and allows the system to work automatically. The size of the tank usually depends on the amount of water produced by the pump in 1 to 2 minutes. The amount of water delivered by the pressure tank between the time the pump shuts down and the time it starts up again is called the drawdown.
The drawdown is typically much smaller than the overall size of the tank. Common pressure tank sizes range from 10 gallons to over gallons. Tanks holding 20 to 44 gallons, which have a drawdown of 5 to 16 gallons, are the most frequently used. Larger tanks, or more than one tank, may be needed for low-yield wells or systems with high water demands. The most common type of pressure tank design has a diaphragm or bladder, which provides a permanent separation between the air and the water in the tank.
If the air and water are not separated, the water can eventually absorb all the air in the tank, a condition called waterlogging. Groundwater users would find life easier if the water level in the aquifer that supplied their well always stayed the same. Seasonal variations in rainfall and the occasional drought affect the "height" of the underground water level.
Withdrawing water from a well causes the water levels around the well to lower. The water level in a well can also be lowered if other wells near it are withdrawing water. When water levels drop below the levels of the pump intakes, then wells will begin to pump air - they will "go dry. Pumping a well lowers the water level around the well to form a cone of depression in the water table. If the cone of depression extends to other nearby wells, the water level in those wells will be lowered.
The cone develops in both shallow water-table and deeper confined-aquifer systems. In the deeper confined-aquifer system, the cone of depression is indicated by a decline in the pressure and the cone spreads over a much larger area than in a water-table system. For a given rate of withdrawal, the cone of depression extends deeper in low-yielding aquifers than in high-yielding ones. Even though water is present at some depth at almost any location, the success of obtaining an adequate domestic supply usually 5 gallons per minute of water from a well depends upon the permeability of the rock.
Where permeable materials are near land surface, a shallow well may be adequate. Elsewhere, such as where clayey material directly overlies bedrock, a deep well extending into bedrock may be needed. Many people in the United States and worldwide supply their own water for their homes, often in more rural locations that don't have large public-supply water systems to supply water.
Here is a basic diagram showing how these wells function. Although this diagram shows a single home, large wells that supply more customers work generally the same.
Below are descriptions of the basic components found in a private water well. Source: National Ground Water Association. Geological Survey, , by Roger M. Quiz icon made by mynamepong from www.
Want to learn more about groundwater wells? Groundwater is one of our most valuable resources—even though you probably never see it or even realize it is there. There is water somewhere beneath your feet no matter where on Earth you live. Groundwater starts as precipitation, just as surface water does, and once water penetrates the ground, it continues moving, sometimes quickly and sometimes very slowly.
Eventually groundwater emerges Learn about the quality and availability of groundwater for drinking, where and why groundwater quality is degraded, and where groundwater quality is changing. How much do you know about the water below your feet? The National Water Quality Program seeks to answer four questions regarding the quality of our freshwater resources: 1 What is the quality of the Nation's streams and groundwater?
Commercial pesticide applicators, farmers, and homeowners apply about 1 billion pounds of pesticides annually to agricultural land, non-crop land, and urban areas throughout the United States. The use of pesticides has helped to make the United States the largest producer of food in the world and has provided other benefits, but has also been accompanied by concerns about their potential Groundwater will normally look clear and clean because the ground naturally filters out particulate matter.
But did you know that natural and human-induced chemicals can be found in groundwater even if appears to be clean? Below is a list of some contaminants that can occur in groundwater. Artesian water is really not different from other groundwater, except for the fact that it flows to the land surface because pressure in the rocks underground force it to the surface.
But, having water flow to the surface naturally is a handy way to tap groundwater resources. Most of us don't have to look for water.
Proper well location and construction are key to the safety of your well water. The well should be located so rainwater flows away from it. If this water pools near your well, it can seep into it and potentially cause health problems.
Appropriate well construction depends on local geologic and groundwater conditions. Your state water-well contractor licensing agency, your local health department, or a local water system professional can provide information on proper well construction. Make sure any water-well drillers and pump-well installers you work with are bonded and insured.
If required in your state, make sure your ground water contractor is licensed and certified. Visit the National Ground Water Association to find certified water well contractors near you.
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